380 



U. S. p. E. E. EXP, AND SUEVEYS — ZOOLOGY — GENEEAL EEPOET 



Comparative measurements of species. 



POLIOPTILA GAERULEA, Sclater, 



Blue-Gray Flycatcher, 



■Molacilla caeruka, Linnaecs, Syst. Nat. 1, 1766, 43, — Gmelih, I, 1788, 992. 



Sylvia caerulea, Lath. Ind. Orn. II, 1790. — ^Vieillot, Gis. Am. Sept. II, 1807, 30; pi. Ixxxviii. — Bon. Obs. Wils. 



1825, No. 119. 

 Muscicapa caerulea, Wilson, Am. Orn. II, 1810, 164; pi. xviii, f. 3.— Acd. Orn. Biog. 1,1831,431; pi. 84. — 

 NnxTALL, I, 1832,297. 



Culicivora catntlea, Eon. List, 1638.— Ib. Consp. 1850 Aud. Syn. 1839, 42.— Ib. Birds Amer. I, 1840, 244 ; pi. 70. 



Sylvania caerulea, Ndttali,, Man. I. 2d ed. 1840, 337. 



Polioptila caerulea, Sclater, Pr. Zool. Soc. 1855, 11. 



Molacilla cana, Gmei.in, Syst. Nat. I, 1788, 973. 



Sylvia cana, Latham, Ind. Orn. II, 1790, 543. 



? Culicivora mexicana, Bonaf. Consp. 1850, 316. Female. (Not of Cassin.) 



Sp Ch. — Above grayish blue^ gradually becoming bright blue on the crown. A narrow frontal band of black extending 

 backwards over the eye. Under parts and lores bluish white tinged with lead color on the sides First and second tail feathers 

 white except at the extreme base, which is black, the color extending obliquely forward on the inner web ; third and fourth 

 black, with white tip, very slight on the latter ; fifth and sixth entirely black. Upper tail coverts blackish plumbeous. Quills 

 edged externally with pale bluish gray, which is much broader and nearly white on the tertials. Female without any black 

 on the head. Length, 4.3li ; wing, 2.15 ; tail, 2.25. (Skin.) 



Bab. — United States from Atlantic to Missouri, and on the southern border from the Gulf of Mexico to the coast mountains 

 of California. South to Guatemala, 



In addition to the above characters there is a narrow white ring round the eye. The lores 

 are rather paler than the cheeks. The black above the eye runs out into a point a little 

 behind it. 



The exposed portion of the first or spurious quill is less than half that of the second. This is 

 intermediate between the seventh and eighth. The fourth quill is rather longer than the third 

 and fifth. The narrow tail feathers are long and linear. They are moderately graduated; the 

 outer about a quarter of an inch less than the middle. 



Specimens vary somewhat in the amount of black on the forehead, as well as the purity of 

 the whitish on the tertiaries. All the white feathers of the tail have black shafts, sometimes 

 the white tip of the fourth feather is wanting. The feathers of the rump are decidedly whitish 

 towards their base, though this is not visible except when they are separated. Some entirely 

 white are concealed by the others. 



Specimens from Tamaulipas difi'er in a more attenuated bill, and in having the black super- 

 ciliary line bordered below on the lores and before and above the eyes by bluish white, rather 



